Compressor



April 24,1928. 1,667,233

B. S. AIKMAN COMPRESSOR Filed April 14, 1927 Hlm Patented Apr. 24,. 1'928.

UNITED STATES 1,667,233 PATENT OFFICE.'

BURTON S. AIKMAN, OIIEA MILWAUKEE, WISCONSIN, ASSIGNOR TO NATIONALv BRAKE ELECTRIC COMPANY, OF MILWAUKEE, WISCONSIN, A CORPORATION F WIS- CON SIN.

COMPRESSOR. i

I Application led April lfl, 1927*.v Serial No. 183,652.

My invention relates to pumps and more particularly to pneumatic pumps such as compressprs, suction pumps and the like.

. The present invention is more particularly 5`concerned with the valve mechanism vand discharge connections suitable for use on gas compressors. v

In the develo ment of a compressor suitable for operation at speeds above what is now standard in the art I have taken 'up the sleeve valve first proposed by Renault and developed the same to a point where I have been able to run the compressor at full motor speed with air cooling only. See my co-pendlng application Serial No. 180,433, filed April 2, 1927. In the construction therein descrlbed, I have employed a pneumatically operated seat member for holding a seal upon thel intake valve sleeve. The discharge valve in that device is in a 'separate discharge valve chamber andis subjected on itstop side to the heat of the compressed gases and on its bottonr side it lies over the discharged lvalve port which therein constitutes a substantiallyY dead space.

In accordance with the present in'ventin I extend the aforesaid valve seat which structurally is a thin annular plate, radially La inward and cause it to overhang a valve seat which forms a seal against the escape `of compressed air back ninto the cylinder.` This annular plate which forms the seatfor the intake lvalve (sleeve thereby forms the discharge check valve. The pressure which the intake valve sleeve exerts vupon said annular platefassists the pneumatic pressure in opening the discharge check valve.y

l Upon recessional motion of the piston the lo discharge check valve promptly closes and the intake valve cannot open until the discharge check valve has closed.- The vintake passageway conducts the air takeninto the "cylinder directly in contact m lar plate cooling the same...

`In order to prevent the cumulative rise of temperature in ,the pocket above Athe discharge check valve, I havereduced the volunietricsize of the pocket and the passagei0 ways 'communicating therewith to a mini- -mumand-insulated the same from thermal contact with the cylinder walls so that even Yif heating of a part ofithe structure does acilr it@ @91.19F injure 'either ,the valve struemechanism in the The valve of' `my invention is adapted to i beused with the sleeve valve actuated either by ring friction or by mechanical means.-

The actuation of the valve sleeve partly by ring friction and partly by pneumatic pressure constitutes the preferred construction since in that form there is a nice b alance4 between the pneumatic forces operatin to hold .the sleeve valve closedland to hold the discharge check valve closed.

Vhile 'it -would be possible to r have a ring type intake-valve contacting normally with the discharge valve and to permit the pneumatic dierence in pressure on the suction stroke to open the same it is to be ob-` served that such con-struction is not as etfective as the construction employing the sleeve valve where sald sleeve valve has a definite traverse to and from its seat sincev the sleeve valve having such definite trav- Y erse is self-cleaning;

Now in orden'to acquaint those skilled in I shall describe in connection with the accompanying drawing a specific embodiment of the same. l'

Fig. 1 is alongitudinal Vvertical section through the upper end of the cylinder and head, showing the valve mechanism ofthe compressor inthe position it-occupies during the intake stroke of the piston; E

Fig. 2 isa like section showing the valve osition it occupies during the discharge s'tro e;

Fig. 3 isa fragmentary sectional vi'eiv'ot` a modified form in which the sleeve valve is operated by a cam`;

Fi 4 is a fragmentary sectional view showing a modified form of the' valve seat for the intakeand discharge valves.

Referring now tothe vstructure shown in Figures 1 andA 2, the compressor comprises a cylinder 1,v having a head 2,the`se parts and 4 respectively. The upper end of the cylinder 1 comprises an annular air chest or A trunk 5, `communicating with lintake passageway 6. Air is preferably forced into said trunk. under pressure inaccordance with my prior Patent 1,611,866 for scavengi and super-charging the cylinder. The .hep

2 is provided with' radiating fins and the cylinder. may likewise be so provided. The

` annular shoulder 9 to form a tight closure.

head 2, has an opening 7 therethrough, this opening extending through a hollow boss 8 which comprises substantially no more than a cylindrical flange extending from the top of the head, this opening being closed `at the lower end by a-plug 10 which seats on the for said opening 7. The plug 1()V has 'a hollow stem 11 extending up through the hollow boss 8 and'this hollow'stem is threaded at 12 to'receive the lower threaded portion of the coupling 13 which coupling has 'a flange 14 resting on the upper edge of the cylindrical hollow boss 8. The coupling 13 furthermore All has a threaded socket at 15 for receiving the lower end of the discharge pipe'l which surrounds the upper end of thehollow stem 11. By drawing the coupling 14 tight o n the thread 12 the plug 10V which seats against the annular shoulder 9 is drawn tight to form a seal. A dead pocket 17 is thereby insulating medium.

formed in the-hollowV boss 8 to serve as an The plug 10 has 'a plurality of-radial paissageways 18, 18 extending from the periphery thereof to the 'central portion where these passageways communicate with thepassageway 19 in the hollow stem A11. The hollow stem 11 extends up above the .connec-l tion between the coupling 14 and said stem whichV connection occurs at the threaded portion 12 so that the upper end of said hollow stem is insulated thermally from both the discharge pipe 15 and from the coupling 13.

The plug. 10 has at its lower peripheral I' edge an'o'verhang'ing radial flange`20 which provides 'a--fiat Yvalve seat for engagement by the inner margin of a thin annular plate valve the outer margin of which is clamped between a seat 22 and the edge 23 of a clamping ring 24. The seat 22 to wh'ch the outer margin ofthe plate 21 is clam edsprojects downward below the bottom space of the. head 2V so'as to provide a clearance at 25 for the inner free yedge of said valve.- This forms in connection with the annular clearance or passageway 26 the valve chamber for said plate valve 21 and the valve chamber communicates through the radially extend-J ing port 18 with the common discharge passageway19 and the hollow stem 11.

The cylinder' 1 is provided with a movable sleeve 27 within which is fitted the working piston 28 said piston'being reciprocated by the usual crank; shaft in the well known manner. The sleeve 27 constitutes a valve controlling the intake and assisting in controlling the discharge of gas to and fromv the interior'of the same.- ThisY valve sleeve has alight traverse to'and from the check valve 21. At its 'upper end 'it is provided with an inwardly extending flange 29,-

.-having a relatively' narrow seat 30 at its upper edge adapted to engage the bottom surface of the'plate or ring valve 21, be-

tween the seat 20 and the clamping seat 22. The valve sleeve 27 is provided with a flange 31 which is adapted to engage 5a yielding stop 32 which maybe of fibrous composition placed in a groove or seat above the inwardly projecting flange 33 in the wall of the cylinder 1. The flange 33 fits loosely thef outer surface of the valvesleeve 27. The upper end of the sleeve 27 is guided in wing guides 34 depending from the ring 24. A. suitable stationary guide at the bottom end of the sleeve is provided although this is not shown in the drawing.

The operation of the device-shown in Figures 1 and 2 is as follows: Assume that- Y Air enters between theflange 29 and the ring 24, passes in contact with the ring valve 21 between the stationary seat member 2() and engagesthe ange or seat 2O near the` upper end of the valve sleeve and passes down into the interior of the cylinder. It will be observed that the incoming gas thereby contacts directly with the vdischarge check valve andwith the flange 20 which forms the i seat for said discharge check valve "thereby cooling the same. Where the blower describedrin my previously mentioned patent is used 1u connection with a dev1ce' of thlskind the heat which is conveyed to the first part of the incoming Agases is largely dissi- Apated by the excess flow of air created by said blower and the consequent cooling .and

scavenging which results. The air which is blown into the wind chest 5 in excess ofthe requirements oft' the compressor cylinder is discharged against thevtop of thehead for y,

cooling purposes.v

When the piston 28 has reached the bottom of itsstroke the cylinder is full of'air -I at atmospheric pressure or slightly above the same. The piston 28 then begins to riseA and its initial upwardA motion moves the valve sleeve 27 upward to the point where the engaging face 30y of the inturned flange 29 contacts with the ring check valve 21, said check valve remaining closed until such time as the internal pressure in the cylinder is great i 'enough tot` -lift the check valve 21 into the position shownv in Figure 2 whereupon the discharge of compressed gases from thecyl- `inder into 'the annular pocket and Apassageway 26 occurs. From this annular passageway26 the gases pass through the radial Y I passageway 18 into the central` passageway in the hollow stem 11 and from thence,I 13T are discharged on` up into the discharge pipe 16...

There is a nice penumatic balance which controls the operation of the discharge check valve. The ring friction is not suicient to lift the Valve Where any appreciable pneumatic pressure exists above the check valve .but this ring friction is suflieient to apply the sleeve to its seat against the annulaiplate 21 which forms the discharge check valve. As soon as compression within said .cylinder has risen to the point where the the external diameter of the clearance 25 are made substantially equal so that the pneumatic pressure tending to force the valve 21 downward is substantially equal to the pneumatic pressure tending to force the valve sleeve upward.v Ifdesired a slight preponderance of upward pressure may be provided to assist in lifting Athe valve 2l from its seat. I preferably makethe areas of the same diameter s0 that a slightlyhigher pressure must` prevail in the cylinder before the valve 2l is lifted from its seat corresponding to present practice where a discharge check valve is loaded with a spring to compell a slightly higher pressure in the cylinder t0 be generated before the discharge check valve opens. y

The lift of the valve 21 may be made very slight and yet ample discharge opening is provided because of the large diameter of the same with respect to the size f the cylinder.

Since this valve 21 has such a large cfective diameter it isAdesirable to reduce the cont-act of the gases therewith toa minimum to secure the best results. It is undesirable to have a large mass of hot gases remaining in contact with the valve or with the head and for this rea-son I make the annular passageway 26 and the cleara'mrcl 25 above the valve 2l as small as przufticable. AAt the same time Irestrict the passageway IH and the central passageway 1S) to reduce the volumetric content of hot compressed gas and lo compel relatively rapid discharge of the gases therethrough. At the/same time it will he observed that the plug 10 has contact with the head 2 so 'far as the direct transmission -ot heat is concerned only through the narrow seat 9. The central hollow stem 1l is not connected directly to the head and any transmission of heat Jfrom said hollow stem 11 to thehead can occur only through a relatively longpathway which isr exposed to external cooling, this long path of travel of the heat comprising the coupling 13 and the hollow boss 8. The upper end of the hollow stem 1l is surrounded by if deadair space so that the transmission of heat to'or from said hollow stem 11 is retarded to as great an extent as is possible. Any heat passing from the discharge pipe 16 back to the head must follow a relatively long path also exposed to external cooling.

This valve arrangement permits of a reduction of the clearance space to a minimum without projections on the piston.

. I believe that the form of discharge check valve here shown is novel broadly and I am aware that it is not essential that vthe valve sleeve 27 be sealed 'directly against the discharge. valve 21. For example, a separate seat in the form of an annular plate 35 may be provided as shown in Figure 4 for sealing the upper end of the valve sleeve 27 said.

plat-'e' having its free inner edge engaged by 'the upper. edge 30 of said valve sleeve 27. In this form the incoming air cools both the seat 35 and the. discharge check valve 21.

Also it is to be' understood that it is not essential that the valve sleeve be operated solely by ring friction.

.In the modification lustrated in'Figure 3 the intake valve sleeve diagrammatically il- 36 has the straight cylindrical upper end v guided in the guide 38 which extends from the clamping ring 24 corresponding to the guiding finger 34 mounted on the clamping ring 24 shown in Figures 1 and 2. `The upper end of the sleeve 36 is brought into engagement with the annular plate valve 37 the inner margin of which seats on the seat 2() and the outer margin of' which isclamped under the edge 23 of the clamping ring 24.

The valve sleeve 36 is actuated by a` rocking lever 40 pivoted on a stationary pivot at 4l and pivotally connected at 42 to said sleeve 36. At its outer end .the lever 40 is connected bythepin connection 43 with a thrust rod 44 which in turn is pivoted at 45 to the lower rocking vlever 46. This lower rocking lever 46 is pivotedat 45 to the thrust rod 44. This lower rocking lever 46 has a stationary pivot at 47 and has a cam follower 48 in the shape of a roller engaging the cam 49 on the crank shaft 50. The follower 48v is h'cld in contactkwith the cam 49 by a compression spring 5l which bears against. a stationary web 52 through which the stem or rod 44 passes. This Form of intake valve and cam operating mechanism is disclosed in my co-pending application Serial No. 185.713. filedv July 28, 1927, to which reference is'here made for a detailed description and illustration of the same.

In the present construction the plate 37 has suflicient yield that when the valve sleeve 36 is raised in contact with the same the inner inargin will not leave the seat 22 sleeve36may engage a separate'seat such as the yielding plate 23 shown in Figure 4. In other words a separate seat may be provided for the intake valve sleeve without departing from the broad aspect of the invention.

@ne great advantage of the present invention is the ability to open the discharge check valve wit-hout any appreciable preponderanceA of pressure in the cylinder. This means faster delivery of the compressed gas, greater volumetric eicien'cy and better overall eiiciency.

In practice the ring friction and counter vpressure due to the spring of the valve 2l substantially balance each other with the result that very little excess pressure opens the valve. If desired the ring friction may v be greater than the counter spring pressure of the valve.

I do not intend to be limited tothe details shown and described.

I claim: Y

1. In a device of the class described, a cylinder having a head therefor, a valve sleeve in said cylinderf a piston in 'said sleeve, an annular plate secured -at its outer margin to said head, a circular plate secured to said head, said plate having a flange extending radially outward beyond the inner l edge' of the annular plate to form a valve seat engaged by the inner margin of said annular plate, vsaid valve sleeve being adapted to engage the annular late and form a pneumatic seal in conjunction therewith.

cylinder having a. head, said head having an aperture, a plug closing said aperture, said plug havin margin spaced from the hea'd and contacting with the flange to form ay valve, the' outer margin of said annular plate being clamped .passageway and the chamber. v

3. YIn a'compressor, a head member havin axeentral opening-theiethrough, fsa id he f having a. cylindrical flange about said opening Aa circular shoulder about sa'id opening a plug member seated against sud shoulder;

a radially extending: flange at `its lower e ge, an annular plate loosely embracing'said plug and having a,V free lnnerand forming a closure for the openingisaid A plug having a radially extending flange at Y its periphery and having a hollow stem, there being passageways from the periphery ofthe plug above said radial flange to said hollow stem, a thin annular plate valve seatingV upon said radial flange and a threaded coupling member 'connected to said hollow stem, and bearing against said cylindrical iange to keep the plug member seated against the shoulder.

4f. In a con'ipressor, a head member having -a central opening therethrough, said head having a cylindrical flange about said opening, a circular shoulder about said opening, a plug member seated agalnst said shoulder,

and forming a closure for the opening, said plug having a radially extending flange at its periphery and having a hollow stem, there being passageways from the periphery of the plug above saidl radial flange to said hollow stem, a thin' annular plate valve seating upon said radial flange, a threaded coupling member connected tosaid hollow stem Vand bearing 'against said cylindrical iange to keep the plug member seated against the shoulder, said coupling. member having a threaded socket and a discharge pipe loosely threaded Y by the piston to sweep past and cool thesaid discharge valve.

6. In a compressor, a cylinder having a head, said head having an annular discharge passageway, an annular plate valve for said passageway, a piston and a cylindrical in- 2. In a compressor, the combination ofa take valve sleeve, said -sleeve engaging said annular plate valve, upon the dischar stroke of the piston and tending to lift the same from its seat. r

7 In a compressor, the combination of aA cylinder having 'a head, said head 'having an' annular discharge passageway, an' annular plate valve forsaid passageway, said cylin- Ader havingvan annular intake pocket, a cylindrical valve sleeve having a traverse toward land awayY from said annulaiplate lvalve,

said sleeve having a piston therein and being adapted to be opened upon the suction stroke of t e piston, said valve when open permitting' the iston to draw air fromsaid annual inta e `pocket past said annular gdischar valve to cool the same.

. 8. a' compressor, s, cylinder havingA a head, said head having an annular discharge passageway, an annular valve Sett, on annu- I mamas lar plate valve sealed to the head about its outer periphery and seating on said annular valve scat to control said discharge passageway, an intake valve sleeve and a piston therein, said sleeve upon the beginning of the discharge stroke of the piston being forced into-contact with said plate valve and tending to lift it from its seat.

L 9. In a compressor, a cylinderfa head therefor, a piston for the cylinder, said head having a discharge port, a discharge valve controlling the port, an inlet valve sleeve and means for pressing the sleeve against the discharge valve during the compression `stroke of the piston.

10. In a. compressor, the combination of a cylinder, a head having an annular discharge passageway and providing an annular valve seat at the inner periphery of the same, a thin annular plate valve closing said passageway, the outer edge of said valve being rigidly 'clamped to the head, the inner edge being free to move to and from said seat and an intake valve sleeve having a seat disposed radially outside the aforesaid seat, said cylinder and head having an intake passageway, one wall of which is delined by said plate valve.

11. In a compressor, the combination of a cylinder, a head therefor, said compressor having an intake passageway and' a discharge passageway, an intake valve, a piston for said cylinder, said intake valve being movable to open and closethe intake passageway, a discharge valve, said intake valve seating against said discharge valve at the beginning of the compression stroke to close the Vintake passageway and said-discharge valve being unseated by pneumatic pressure after it is engaged by said intake valve.

12. In a compressor, a cylinder, a head therefor, a piston for the cylinder, said' compressor having an intake passageway and discharge passageway adapted to com-v municate with the interior of the cylinder, said discharge passageway having an annular valve seat, an annular plate valve clamped to said head about its outer margin and seating upon said seat at its inner margin, andan intake valve sleeve in the cylin` der controlling the intake passageway and seating when closed against said discharge check valve. A

13. In a compressor, the combination of a frame, a head secured thereto` an intake valve sleeve cooperating with the head to form a working cylinder, a. piston in said cylinder, said compressor having an intake passageway controlled by said sleeve, a discharge passageway, a thin annular plate valve controlling said discharge"passageway and forming when closed one wall of the intake passageway. v

14. In a compressor, the combination of a frame, a head secured thereto, an intake valvel sleeve cooperating with the head to form a working cylinder, a piston in said cylinder, said compressor having an intake passageway controlled by said sleeve, a discharge passageway, a thin annular plate valve controlling saiddischarge passageway forming when closed one wall of the intake passageway, said. valvcsleeve when closed vsleeve slidably mounted in the frame and cooperating with lhe head tozdeine a working chamber, an annular intake valve passageway surrounding the upper end of said sleeve, an annular clamping'seat on the bottom of the head, an annular valve seat depending fronrsaid head, a thin annular plate valve secured to the clamping seat and coop- 'erating withthe other seat to form avdischarge cheek valve, said intake valve sleeve being adapted to engage said thin annular plate between the clamping seat and the depending seat. i

17. In combination, a cylinder frame, a head secured thereto, a valve sleeve mounted in the frame, a central opening through the head, a tubular extension on the head sur? rounding said 0pening,van annular shoulder about the lower end of the opening, a plug 'member seating against said Ishoulder, said plug member having a hollow stem, a coupling member resting on the upper end of said tubular extension and engaging the hollow stem, said coupling having a threaded pipe socket for receiving a discharge pipe.

18. In combination, a cylinder head having an opening therethrough, a tubular eX- tension on' the head surrounding the opening, a circular plug closing the lower end of the opening, said plug having a hollow stem eX- tending out tlrough the tubular extension, a

coupling having a flange overhanging the edge of the tubular extension and having a body displaced axially from said flange and secured to the `hollow stein, said coupling having a pipe socket :for connecting a discharge pipe. f l

19. In combination, aA cylinder head hav- 'ing an opening therethrough, a tubular eX- tension on the head surrounding the opening, a circular plug closing the lower end of the opening, said plug having a hollow stem extending out through the tubular extension,

.evt

i a coupling having a flange overhanging the edge of the tubular extension and having a secured to the hollow stem, said coupling having a' pipe-'socketfor connecting al dis.

charge pipe, said plug having a radially extendlngange below the surface ofthe head and an annular plate valve cooperating with said flange to form a discharge check valve.

20. In a compressor, having a head provided with a discharge passageway, a cylinder provided with an intake passageway an an intake sle-eve valve there being an annular passageway between the sleeve and Athe head, the lower end of said passageway communicating with the interior of the sleeve valve, the upper end of the annular passageway bel ing adapted to communicate alternately with Leeidas the intake passageway and the discharge passageway, the sleeve valve controlling sald communication with the intake passageway and a check valve controlling said communication with the discharge passageway. Y

21. In combination, a cylinder head having an annular1 seat, a ring valve of thin metal having its outer peripheral margin disposed on; said seat, a. clamping ring for clamping said outer vmargin on said seat, said head providing a clearance under the inner means providing an egternal seat for the free margin of said Valve.

In witness whereof, I hereunto subscribe peripheral margin of said ring valve, and *80 

